Many spacecraft include one or more payloads that are released after the spacecraft attains orbit. During spacecraft launch, relatively large vibration and thrust loads may be imparted on the payloads. Thus, payloads are typically mounted on the spacecraft using launch lock devices that are configured to both restrain the payloads against these vibration and thrust loads, and to subsequently release the payloads when the spacecraft attains orbit.
Commonly used launch lock devices are configured to release a payload by breaking a bolt using either pyrotechnics or a shape memory alloy (SMA). While generally safe, reliable, and robust, these launch lock devices do exhibit certain drawbacks. For example, breaking the bolt may transmit relatively high loads from high frequency acceleration (e.g., shock) to the payload. This can potentially cause damage to the payload.
Low-shock launch lock devices have been utilized using various techniques, some involving SMA materials that are used to stretch a bolt instead of breaking a bolt, thereby opening a gap and releasing the payload. This gap equates to a payload range of motion before stops are hit. Current state of the art approaches for such devices have limited dynamic ranges, and therefore result in the payload having a limited range of motion allowable, due to the specific implementation details.
Hence, there is a need for a payload launch lock device that sufficiently restrains a payload during launch, that subsequently releases the payload without transmitting relatively high loads to the payload (i.e. low shock), and increases the available range of payload motion. The present invention addresses at least this need.